[Paleontology • 2009] Raptorex kriegsteini • Tyrannosaurid skeletal design first evolved at small body size

Fig. 1: Skull, endocast, and premaxillary teeth of the Early Cretaceous tyrannosauroid R. kriegsteini. 

Nearly all of the large-bodied predators (>2.5 tons) on northern continents during the Late Cretaceous were tyrannosaurid dinosaurs. We show that their most conspicuous functional specializations—a proportionately large skull, incisiform premaxillary teeth, expanded jaw-closing musculature, diminutive forelimbs, and hindlimbs with cursorial proportions—were present in a new, small-bodied, basal tyrannosauroid from Lower Cretaceous rocks in northeastern China. These specializations, which were later scaled up in Late Cretaceous tyrannosaurids with body masses approaching 100 times greater, drove the most dominant radiation of macropredators of the Mesozoic.

Fig. 2: Postcranial features of the Early Cretaceous tyrannosauroid R. kriegsteini.

Fig. 4: Temporal, geographic, and phylogenetic patterns among tyrannosauroids. 

(A) Temporally calibrated phylogeny of tyrannosauroids based on phylogenetic analysis, showing an early diversity of basal tyrannosauroids (shaded) from localities across Laurasia and plotted on an Early Cretaceous paleogeographic map. Proceratosaurus and Xiongguanlong were excluded from this plot because of limited available morphologic data and age uncertainty, respectively. 

(B) Phylogram scaled to the amount of character change (delayed transformation) 

Circled nodes 1 to 3 outline major transformations in tyrannosauroid evolution. Taxonomic definitions of Tyrannosauroidea, Tyrannosauridae, and other taxa follow. 

Abbreviations for biogeographic area and localities: A, Asia; E, Europe; NA, North America; 

1, Stokesosaurus; 2, Proceratosaurus and Eotyrannus; 3, Aviatyrannis; 4, Guanlong; 5, Dilong; 6, Xiongguanlong; 7, Raptorex.

Sereno, P.; Tan, L.; Brusatte, S. L.; Kriegstein, H. J.; Zhao, X. & Cloward, K. (2009). "Tyrannosaurid skeletal design first evolved at small body size". Science. 326 (5951): 418–422. doi:10.1126/science.1177428

http://www.sciencemag.org/content/326/5951/418.figures-only

http://scienceblogs.com/notrocketscience/2009/09/raptorex_tiny_king_of_thieves_shows_how_tyrannosaurus_body_p.php

http://blogs.discovermagazine.com/80beats/2010/09/17/how-tyrannosaurs-grew-from-tiny-jackals-to-ferocious-giants/

[Paleontology • 2011] Reanalysis of “Raptorex kriegsteini”: A Juvenile Tyrannosaurid Dinosaur from Mongolia

The carnivorous Tyrannosauridae are among the most iconic dinosaurs: typified by large body size, tiny forelimbs, and massive robust skulls with laterally thickened teeth. The recently described small-bodied tyrannosaurid Raptorex kreigsteini is exceptional as its discovery proposes that many of the distinctive anatomical traits of derived tyrannosaurids were acquired in the Early Cretaceous, before the evolution of large body size. This inference depends on two core interpretations: that the holotype (LH PV18) derives from the Lower Cretaceous of China, and that despite its small size, it is a subadult or young adult. Here we show that the published data is equivocal regarding stratigraphic position and that ontogenetic reanalysis shows there is no reason to conclude that LH PV18 has reached this level of maturity. The probable juvenile status of LH PV18 makes its use as a holotype unreliable, since diagnostic features of Raptorex may be symptomatic of its immature status, rather than its actual phylogenetic position. These findings are consistent with the original sale description of LH PV18 as a juvenile Tarbosaurus from the Upper Cretaceous of Mongolia. Consequently, we suggest that there is currently no evidence to support the conclusion that tyrannosaurid skeletal design first evolved in the Early Cretaceous at small body size.

Fowler DW, Woodward HN, Freedman EA, Larson PL, Horner JR (2011) Reanalysis of “Raptorex kriegsteini”: A Juvenile Tyrannosaurid Dinosaur from Mongolia. PLoS ONE. 6(6): e21376. doi:10.1371/journal.pone.0021376

Fig. 1: Skull, endocast, and premaxillary teeth of the Early Cretaceous tyrannosauroid R. kriegsteini. 

Nearly all of the large-bodied predators (>2.5 tons) on northern continents during the Late Cretaceous were tyrannosaurid dinosaurs. We show that their most conspicuous functional specializations—a proportionately large skull, incisiform premaxillary teeth, expanded jaw-closing musculature, diminutive forelimbs, and hindlimbs with cursorial proportions—were present in a new, small-bodied, basal tyrannosauroid from Lower Cretaceous rocks in northeastern China. These specializations, which were later scaled up in Late Cretaceous tyrannosaurids with body masses approaching 100 times greater, drove the most dominant radiation of macropredators of the Mesozoic.

Fig. 2: Postcranial features of the Early Cretaceous tyrannosauroid R. kriegsteini.

Fig. 4: Temporal, geographic, and phylogenetic patterns among tyrannosauroids. 

(A) Temporally calibrated phylogeny of tyrannosauroids based on phylogenetic analysis, showing an early diversity of basal tyrannosauroids (shaded) from localities across Laurasia and plotted on an Early Cretaceous paleogeographic map. Proceratosaurus and Xiongguanlong were excluded from this plot because of limited available morphologic data and age uncertainty, respectively. 

(B) Phylogram scaled to the amount of character change (delayed transformation) 

Circled nodes 1 to 3 outline major transformations in tyrannosauroid evolution. Taxonomic definitions of Tyrannosauroidea, Tyrannosauridae, and other taxa follow. 

Abbreviations for biogeographic area and localities: A, Asia; E, Europe; NA, North America; 

1, Stokesosaurus; 2, Proceratosaurus and Eotyrannus; 3, Aviatyrannis; 4, Guanlong; 5, Dilong; 6, Xiongguanlong; 7, Raptorex.

Sereno, P.; Tan, L.; Brusatte, S. L.; Kriegstein, H. J.; Zhao, X. & Cloward, K. (2009). "Tyrannosaurid skeletal design first evolved at small body size". Science. 326 (5951): 418–422. doi:10.1126/science.1177428

http://www.sciencemag.org/content/326/5951/418.figures-only

http://scienceblogs.com/notrocketscience/2009/09/raptorex_tiny_king_of_thieves_shows_how_tyrannosaurus_body_p.php

http://blogs.discovermagazine.com/80beats/2010/09/17/how-tyrannosaurs-grew-from-tiny-jackals-to-ferocious-giants/

Tyrannosaur Paleobiology: New Research on Ancient Exemplar Organisms

http://www.sciencemag.org/content/329/5998/1481.abstract

[Paleontology • 2010] Family Proceratosauridae: [a coelurosaur, a tyrannosauroid] • hylogenetic position of the theropod dinosaur Proceratosaurus bradleyi from the Middle Jurassic of England

Figure 1. Proceratosaurus bradleyi, type skull: NHM R 4860.

The cranial osteology of the small theropod dinosaur Proceratosaurus from the Bathonian of Minchinhampton, England, is described in detail, based on new preparation and computed tomography (CT) scan images of the type, and only known, specimen. Proceratosaurus is an unusual theropod with markedly enlarged external nares and a cranial crest starting at the premaxillary–nasal junction. The skull is highly pneumatic, with pneumatized nasals, jugals, and maxillae, as well as a highly pneumatic braincase, featuring basisphenoid, anterior tympanic, basipterygoid, and carotid recesses. The dentition is unusual, with small premaxillary teeth and much larger lateral teeth, with a pronounced size difference of the serrations between the mesial and distal carina. The first dentary tooth is somewhat procumbent and flexed anteriorly. Phylogenetic analysis places Proceratosaurus in the Tyrannosauroidea, in a monophyletic clade Proceratosauridae, together with the Oxfordian Chinese taxon Guanlong. The Bathonian age of Proceratosaurus extends the origin of all clades of basal coelurosaurs back into the Middle Jurassic, and provides evidence for an early, Laurasia-wide, dispersal of the Tyrannosauroidea during the late Middle to Late Jurassic.

Keywords: Bathonian; biogeography; Coelurosauria; phylogeny; Proceratosauridae; Tyrannosauroidea

Figure 2. Proceratosaurus bradleyi, type skull: NHM R 4860. Stereophotographs

Figure 24. Stratigraphic distribution and ghost lineages in basal coelurosaurs, especially tyrannosauroids.

Figure 26. Biogeographic distribution of Jurassic tyrannosauroids. 

1, Proceratosaurus bradleyi, Great Oolite, England (Bathonian); Stokesosaurus langhami, Kimmeridge Clay, England (Tithonian); 2, Guanlong wucaii, Shishougou Formation, Xinjiang, China (Oxfordian); 3, Aviatyrannis jurassica, Guimarota Beds, Portugal (Kimmeridgian); 4, Stokesosaurus clevelandi, Morrison Formation, Utah, USA (Kimmeridgian–Tithonian).

Rauhut, O.W.M., Milner, A.C. and Moore-Fay, S. (2010). "Cranial osteology and phylogenetic position of the theropod dinosaur Proceratosaurus bradleyi (Woodward, 1910) from the Middle Jurassic of England". Zoological Journal of the Linnean Society. doi: 10.1111/j.1096-3642.2009.00591.x

Brusatte, S.L.; Norell, M.A.; Carr, T.D.; Erickson, G.M.; Hutchinson, J.R.; Balanoff, A.M.; Bever, G.S.; Choiniere, J.N.; Makovicky, P.J.; and Xu, X. (2010). "Tyrannosaur paleobiology: new research on ancient exemplar organisms". Science 329: 1481−1485. doi: 10.1126/science.1193304

https://sites.google.com/site/Brusatte/

[Paleontology • 2010] Kileskus aristotocus • A basal tyrannosauroid (Dinosauria: Theropoda) from the Middle Jurassic of Siberia, Russia

http://atrox1.ucoz.ru/photo/10-0-399-3

A.O. Averianov, S.A. Krasnolutskii and S.V. Ivantsov, 2010. A new basal coelurosaur (Dinosauria: Theropoda) from the Middle Jurassic of Siberia. Proceedings of the Zoological Institute RAS. Volume 314 (1): 42-57.

http://www.zin.ru/journals/trudyzin/doc/vol_314_1/TZ_314_1_Averianov.pdf

http://en.wikipedia.org/wiki/Kileskus

http://paleopedia.wikia.com/wiki/Kileskus

[Paleontology • 2009] Sinotyrannus kazuoensis • First large basal proceratosaurid theropod from the Early Cretaceous Jehol Biota in northeastern China

Sinotyrannus is a genus of proceratosaurid tyrannosauroid. Despite being not much younger than Dilong, another basal tyrannosaur, Sinotyrannus was very large in size (10 m), closer to that of Tyrannosaurus than Dilong. 

Sinotyrannus is known from a single incomplete fossil specimen including a partial skull, from the Early Cretaceous Jiufotang Formation (app.120 million years ago) of Liaoning, China.

Ji, Q.; Ji, S.-A.; Zhang, L.-J. 2009. First large tyrannosauroid theropod from the Early Cretaceous Jehol Biota in northeastern China. Geological Bulletin of China 28 (10): 1369–1374.

http://xa.yimg.com/kq/groups/1225428/375768469/name/20091001.pdf

http://en.wikipedia.org/wiki/Sinotyrannus

http://paleopedia.wikia.com/wiki/Sinotyrannus

[Paleontology • 2006] Guanlong wucaii 'crown dragon' • A proceratosaurid tyrannosauroid dinosaur from the Late Jurassic of China

An artist rendering of Guanlong wucaii, the newly discovered basal tyrannosauroid, oldest known cousin of the Tyrannosaurus rex.

Credit: Zhang Zongda/IVPP

Guanlong wucaii skull | Photo Credit: IVPP 

Guanlong wucaii skull rendering  | Photo Credit: R.S. Li, IVPP 

Theropoda Marsh, 1881

Coelurosauria von Huene, 1914

Tyrannosauroidea Osborn, 1905

Proceratosauridae Rauhut, Milner & Moore-Fay, 2010

Guanlong wucaii gen. et sp. nov.

Etymology. The generic name is derived from the Chinese Guan (crown) and long (dragon); the specific name is from the Chinese wucai (five colours), which refers to the rich colours of rocks that produced the specimens.

Holotype. IVPP (Institute of Vertebrate Paleontology and Paleoanthropology, Beijing) V14531 is a partly articulated skeleton preserving most of the elements.

Referred material. IVPP V14532 is much smaller than the holotype and is a fully articulated, nearly complete skeleton.

Locality and horizon. Wucaiwan area, Junggar Basin, Xinjiang; Oxfordian upper part of the Shishugou Formation. 

Xu X., Clark, J.M., Forster, C. A., Norell, M.A., Erickson, G.M., Eberth, D.A., Jia, C., and Zhao, Q. 2006. A basal tyrannosauroid dinosaur from the Late Jurassic of China. Nature 439 (7077): 715–718. doi:10.1038/nature04511

'Crowned dragon': This reconstruction of the head of Guanlong wucaii is based on Xu and colleagues, the most notable feature being the crest, which may have been used in visual display. 

(Drawing by Zhongda Zhang, reproduced by courtesy of the Institute of Vertebrate Paleontology and Paleoanthropology, Beijing.)

 Guanlong wucaii in evolutionary context:

The bipedal and carnivorous theropod dinosaurs first appeared around 235 million years (Myr) ago in the Triassic period, later diverging into several different lines. In particular, during the Jurassic, one lineage (the Avetheropoda) divided into the Carnosauria and Coelurosauria, the latter including the Tyrannosauroidea. Certain primitive features of the two Guanlong fossils show that Guanlong lies at the base of the lineage of the tyrannosauroids, and close to the divergence between the major lineages of coelurosaurs. Numbers in parentheses indicate adult length.

Two small Guanlong wucaii dinosaurs struggle to escape a muddy pit in what is now China during the late Jurassic period.

Illustration courtesy Michael Skrepnik

http://www.gwu.edu/~newsctr/fossilfind/

http://ngm.nationalgeographic.com/2008/07/tyrannosaur-trap/gwin-text

New Dinosaur Is Oldest Cousin of Tyrannosaurus Rex: http://bit.ly/HgViBZ  

http://www.dinosaures-web.com/dinotopia/category/liste-des-dinosaures/alioramus

[Insect • 2012] Megalara garuda | Garuda Wasp, Sulawesi Giant Wasp • a new genus and species of larrine wasps from Indonesia (Larrinae, Crabronidae, Hymenoptera)

Garuda has been interpreted in Indonesia as a god or eagle, fighting serpents. It's not known what this Garuda preys upon, but it looks capable of mighty deeds; Above is a male Megalara garuda, also known as the King of Wasps 

Credit: Dr. Lynn Kimsey, Dr. Michael Ohl

Megalara garuda Kimsey & Ohl, gen. et sp. n.

Abstract

A new genus and species, Megalara garuda is described from Sulawesi (Indonesia). The new species is one the largest known members of the crabronid subfamily Larrinae. It has a unique suite of putatively apomorphic morphological characters and is most closely related to the genus Paraliris. We found indications of a significant allometric variation in body size and mandibular length and shape in male Megalara, and the presence of acarinaria at least in females of the new genus. Allometric variation and acarinaria have previously been shown to occur in Paraliris, which is another indication for a close relationship of Megalara and Paraliris.

Etymology. The new genus name is an arbitrary combination of Mega-, deriving from the Greek megas, meaning large and mighty, and –lara, the last syllable of Dalara. It is an allusion both to the exaggerated body size of the new genus and its overall similarity to Dalara.

Etymology. Because of the spectacular appearance of the major male of this species, it is named after the “Garuda”, the national symbol of Indonesia; a mythical bird-like, warrior creature.

(Megalara Garuda) The male (3), with its frightening jaws, and the smaller female (4) differ; 

Credit: Dr. Lynn Kimsey, Dr. Michael Ohl

Kimsey, L. and Ohl, M. 2012. Megalara garuda, a new genus and species of larrine wasps from Indonesia (Larrinae, Crabronidae, Hymenoptera). ZooKeys 177: 49. doi:10.3897/zookeys.177.2475.

Meet the just discovered 'Komodo dragon' of wasps: 

http://news.mongabay.com/2011/0828-hance_komodo_wasp.html

Meet the wasp king - Megalara garuda: 

http://www.earthtimes.org/nature/megalara-garuda-wasp-king/1883/

[Insect • 2011] New species of the Australian horse fly subgenus Scaptia (Plinthina) Walker 1850 (Diptera: Tabanidae), including species descriptions and a revised key, including Scaptia (Plinthina) beyonceae

The Scaptia (Plinthina) beyonceae has been named in honour of American pop diva, Beyoncé 

Photo: BRYAN LESSARD/AFP/Getty Images

Abstract

Horse flies (Diptera: Tabanidae) are recognised for their medical and veterinary importance, but they also have an important role in pollination. The genus Scaptia Walker 1850 contains more than 100 species and comprises seven subgenera with an exclusively southern distribution from Australia, New Zealand, New Guinea and South America. Five new Australian species are described in the subgenus Plinthina, which previously comprised only seven species, and an existing key is modified to include the new species, all of which are diagnosed and figured. The new species are: S. (Plinthina) arnhemensis sp.n. Lessard, S. (Plinthina) aurifulga sp.n. Lessard, S. (Plinthina) beyonceae sp.n. Lessard, S. (Plinthina) nelsonae sp.n. Lessard and S. (Plinthina) nigripuncta sp.n. Lessard.

Keywords: Pangoniinae; Plinthina; Scaptia; Tabanidae; taxonomy

The #Beyonce fly: Researchers name insect with golden behind after singer - Telegraph http://www.telegraph.co.uk/science/9012133/The-Beyonce-fly-Researchers-name-insect-with-golden-behind-after-singer.html

http://www.biodiversityinfocus.com/blog/2012/01/13/irreplaceable-fly-described-from-australia/

Lessard, Bryan; Yeates, David (2011). New species of the Australian horse fly subgenus Scaptia (Plinthina) Walker 1850 (Diptera: Tabanidae), including species descriptions and a revised key. Australian Journal of Entomology. 50 (3): 241–252. doi:10.1111/j.1440-6055.2011.00809.x/

[Insect • 2011] Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini) | 11 New Bee Species Discovered in Eastern United States; one named gotham for New York City

A Gotham bee nests underground. 

Credit: Louise Lynch/University of Nebraska-Lincoln

A side (A) and face (B) view of Lasioglossum gotham, a new species that was discovered in the New York Botanical Garden in the Bronx and in the Brooklyn Botanic Garden. 

Credit: Jason Gibbs/Cornell University

| 11 New Bee Species Discovered in Eastern United States. 

New finds include four species from New York; one named Gotham for New York City

http://www.amnh.org/news/tag/gotham-bee/

http://www.amnh.org/science/papers/bees_2011.php

http://www.impactlab.net/2011/11/19/11-new-species-of-bees-discovered/

New York City Buzzing With New Bee Species : http://news.discovery.com/animals/new-bee-species-111121.html

Abstract

Bees in the subgenus Lasioglossum (Dialictus) are commonly collected, behaviourally diverse and taxonomically challenging. The metallic species of Lasioglossum (Dialictus) occurring east of the Mississippi River are revised. Taxonomic treatments of all 97 species are provided with complete descriptions and illustrations given for the 40 species, which have not been recently described elsewhere. Identification keys for males and females are provided.

The following eleven new species are described: Lasioglossum (Dialictus) arantium new species, L. (D.) ascheri new species, L. (D.) batya new species, L. (D.) curculum new species, L. (D.) furunculum new species, L. (D.) georgeickworti new species, L. (D.) gotham new species, L. (D.) izawsum new species, L. (D.) katherineae new species, L. (D.) rozeni new species, and L. (D.) trigeminum new species. Lasioglossum ascheri, L. curculum, L. furunculum, L. izawsum, and L. rozeni are believed to be social parasites or cleptoparasites of nest-building L. (Dialictus). Lasioglossum (D.) smilacinae (Robertson) is resurrected from synonymy with L. laevissimum (Smith). Lasioglossum (D.) nymphaearum (Robertson) is resurrected from synonymy with L. albipenne (Robertson).

Lasioglossum rufulipes (Cockerell) and L. testaceum (Robertson) are removed from Evylaeus and placed in Dialictus.

The following eleven new synonymies are proposed (junior subjective synonym listed second): L. (D.) flaveriae (Mitchell) = Dialictus tahitensis Mitchell; L. (D.) leucocomum (Lovell) = Dialictus otsegoensis Mitchell; L. (D.) lionotum (Sandhouse) = Paralictus asteris Mitchell; L. (D.) longifrons (Baker) = L. (Chloralictus) robertsonellum Michener; L. (D.)  nigroviride (Graenicher) = Evylaeus pineolensis Mitchell; L. (D.) simplex (Robertson) = Halictus (Chloralictus) malinus Sandhouse; L. smilacinae (Robertson) = Halictus zophops Ellis, = D. philanthanus Mitchell; L. (D.) testaceum (Robertson) = Halictus (Chloralictus) scrophulariae Cockerell, = Lasioglossum (Chloralictus) sandhouseae Michener; and L. (D.) versans (Lovell) = Evylaeus divergenoides Mitchell.

Lectotypes are designated for Halictus albipennis Robertson (1890), Halictus albitarsis Cresson (1872), Halictus cressonii Robertson (1890), Halictus disparilis Cresson (1872), Halictus hortensis Lovell (1905), Halictus nubilis Lovell (1905), Halictus pilosus leucocomus Lovell (1908), Halictus planatus Lovell (1905), Halictus stultus Cresson (1872), Halictus subconnexus rohweri Ellis (1915), Halictus tegularis Robertson (1890), Halictus versans Lovell (1905), and Halictus viridatus Lovell (1905).

Key words: Sweat bees, Halictinae, taxonomy, new species, new synonymy, lectotype, DNA barcodin

Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini)

http://www.mapress.com/zootaxa/2011/f/z03073p216f.pdf

[Insect • 2010] Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini)

The newly discovered Toronto bee, Lasioglossum ephialtum. (Credit: Jason Gibbs)

Abstract

The bee subgenus Dialictus (Hymenoptera: Halictidae: Lasioglossum) comprises the most commonly collected bees in North America and have the most diverse social systems of any equivalent group of insects. Despite their importance, as pollinators and as model organisms for studying the evolution of social behaviour, Dialictus remain one of the greatest challenges in bee taxonomy. A taxonomic revision of the metallic species of Canadian Dialictus has been completed which resolves many of the difficulties of these bees. Complete species descriptions with illustrations are provided for 84

metallic Dialictus in Canada along with keys to identify males and females.

The following nineteen new species are described: Lasioglossum (Dialictus) abundipunctum new species, L. (D.) atwoodi new species, L. (D.) dashwoodi new species, L. (D.) ebmerellum new species, L. (D.) ephialtum new species, L. (D.) imbrex new species, L. (D.) knereri new species, L. (D.) lilliputense new species, L. (D.) macroprosopum new species, L. (D.) packeri new species, L. (D.) prasinogaster new species, L. (D.) reasbeckae new species, L. (D.) sablense new species, L. (D.) sandhousiellum new species, L. (D.) sheffieldi new species, L. (D.) sitocleptum new species, L. (D.) taylorae new species, L. (D.) timothyi new species, and L. (D.) yukonae Gibbs, new species. Lasioglossum (D.) mitchelli is proposed as a replacement name for L. atlanticum (Mitchell) due to secondary homonymy with Halictus interruptus atlanticus Cockerell, a junior subjective synonym of L. interruptum (Panzer).The following forty-three new synonymies are proposed:  L.  (D.) admirandum  (Sandhouse) (=  D. perspicuus  Knerer and

Atwood); L. (D.) albipenne (Robertson) (= Halictus palustris Robertson, = H. (Chloralictus) lactineus Sandhouse, = H. (C.) basilicus Sandhouse); L. (D.) albohirtum (Crawford) (= H. pilosellus Cockerell); L. (D.) brunneiventre (Crawford) (= H. pilosicaudus Cockerell); L. cattellae (Ellis) (=D. alternatus Mitchell); L. connexum (Cresson) (= H. (C.) politissimus Cockerell); L. (D.) cressonii (Robertson) (= D. delectatus Mitchell); L. floridanum (Robertson) (= D. intrepidus Mitchell);  L. (D.) foveolatum (Robertson) (= D. supraclypeatus Mitchell); L. (D.) imitatum (Smith) (= H. (C.) insolitus Sandhouse, = D. lectus Mitchell); L. (D.) incompletum (Crawford) (= D. ornduffi Hurd); L. (D.) laevissimum (Smith) (= H. (C.) astutus Sandhouse, = H. (C.) abundus Sandhouse, = H. (C.) jamesae Cockerell, = H. (C.) phaceliarum Cockerell, = H. (C.) praepes Sandhouse, = D. solidaginis Mitchell, = H. (C.) tranquillus Sandhouse); L. (D.) lineatulum (Crawford) (= H. (C.) latus Sandhouse); L. (D.) nigroviride (Graenicher) (= H. (C.) richardsoni Cockerell); L. (D.) obscurum (Robertson) (= D. orbitatus Mitchell); L. (D.) occidentale (Crawford) (= D. theodori Crawford); L. (D). oceanicum (Cockerell) (= D. advertus Mitchell); L. (D.) pavoninum (Ellis) (= H. (C.) evestigatus Sandhouse, = H. (C.) pikei Sandhouse, = H. (C.) abietum Michener); L. (D.) perpunctatum (Ellis) (= D. highlandicus Mitchell, = D. junaluskensis Mitchell); L. (D.) sagax (Sandhouse) (= Halictus (C.) accentus Sandhouse); L. (D.) semibrunneum (Cockerell) (= Halictus oleosus Cockerell); L. (D.) semicaeruleum (Cockerell) (= H. pruinosiformis Crawford, = H. (C.) actuarius Sandhouse); L. (D.) subversans (Mitchell) (= D. perpunctatulus Knerer and Atwood); L. (D.) tenax (Sandhouse) (= H. (C.) meritus Sandhouse, = D.

disabanci Knerer and Atwood); L. (D.) versans (Lovell) (= H. (C.) brevibasis Cockerell); L. (D.) versatum (Robertson) (= H. (C.) apertus Sandhouse, = H. (C.) genuinus Sandhouse, = H. subconnexus rohweri Ellis); L. (D.) zephyrum (Smith) (= H. (C.) academicus Sandhouse). Halictus (C.) unicus Sandhouse is again treated as a junior synonym of L. lineatulum. Eleven subgeneric names recently proposed by Pesenko are treated as synonymies of Dialictus

Some species names are used here in a sense different from those of most previous authors (e.g. H. nymphaearus, H. versatus). Names have often been misapplied in past usage sometimes subsuming multiple species. In some cases, even paratypes do not correspond to the same species as the name bearing type.

The following three species are resurrected from synonymy: L. (D.) leucocomum (Lovell) new combinaton, L. (D.)

oceanicum (Cockerell) new combination, and L. (D.) planatum. 

The species L. (D.) atriventre (Crawford) is considered a nomen dubium.

The following twelve new records for Canada are reported:  L.  (D.) achilleae  (Mitchell),  L.  (D.) brunneiventre (Crawford), L. (D.) callidum (Sandhouse), L. (D.) incompletum (Crawford), L. (D.) hudsoniellum (Cockerell), L. (D.) marinense (Michener), L. (D.) pacatum (Sandhouse), L. (D.) pallidellum (Ellis), L. (D.) punctatoventre (Crawford), L. (D). sagax (Sandhouse), L. (D.) weemsi (Mitchell) and L. (D.) zophops (Ellis). The Canadian records of two species, L. (D.) disparile (Cresson) and L. (D.) ceanothi (Mitchell), do not seem reliable and these species are not included in the revision.

Two species, L. testaceum (Robertson) and L. rufulipes (Cockerell), are transferred from the L.  (Dialictus) to L. (Evylaeus) sensu stricto.

Key words: Sweat bee, new species, new synonymy, taxonomy, DNA barcoding

A York University doctoral student who discovered a new species of bee on his way to the lab one morning has completed a study that examines 84 species of sweat bees in Canada. Nineteen of these species -- including the one Jason Gibbs found in downtown Toronto − are new to science because they have never been identified or described before.

New Bee Species Discovered in Downtown Toronto

http://www.sciencedaily.com/releases/2010/08/100831121439.htm

Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini)

http://www.mapress.com/zootaxa/2010/f/z02591p382f.pdf